https://leetcode.com/problems/number-of-distinct-islands

number-of-distinct-islands.go

const (
    water = 0
    land = 1
    visited = 2
)

var directions = [][2]int{
    {0, 1},
    {1, 0},
    {0, -1},
    {-1, 0},
}

// 0,0,0,0,1,1,1
// 1,1,1,1,1,1,1
// 0,0,0,0,0,0,0
// 0,0,0,0,1,1,1
// 1,1,1,1,1,1,0
// 0,0,0,1,0,0,0

func numDistinctIslands(grid [][]int) int {
    set := make(map[string]bool)
    
    for i := 0; i < len(grid); i++ {
        for j := 0; j < len(grid[0]); j++ {
            if grid[i][j] == land {
                hash := markAsVisited(grid, i, j)
                
                if _, ok := set[hash]; !ok {
                    set[hash] = true
                }
            }
        }
    }
    
    return len(set)
}

// **
//  **
// **

// **
// **
// **

func markAsVisited(grid [][]int, i, j int) string {
    hash := ""
    n, m := len(grid), len(grid[0])
    grid[i][j] = visited
    queue := [][2]int{{i, j}}

    
    for len(queue) > 0 {
        item := queue[0]
        hash += fmt.Sprintf("%d", (item[0] - i) * 2 * len(grid) + (item[1] - j))
        queue = queue[1:]
        
        for _, d := range directions {
            x, y := item[0] + d[0], item[1] + d[1]
            
            if x >= 0 && x < n && y >= 0 && y < m && grid[x][y] == land {
                grid[x][y] = visited
                queue = append(queue, [2]int{x, y})
            }
        }
    }
    
    return hash
}

func equals(grid [][]int, i, j, m, n int) bool {
    return false
}